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All I can say is that you could review this and Pg (304) is the most important


____________________ are bacterial viruses with a polyhedral head and a helical tail, that also eat bacteria.

Rosalind Franklin

a British scientist that studied the DNA molecule using a technique called x-ray diffraction and was able to decipher important clues about its structures


deoxyribonucleic acid; the genetic material that carries information about an organism that is passed from parent to offspring AND is used by an individual as the recipe for making proteins

Hershey and Chase

Used radioactive material to label DNA(P-32) and protein (S -35), then used a blender to separate the phage(T2) from the bacteria(E-Coli), and centrifuged the mixture so that bacteria at bottom formed a pellet, and when analyzed measured the radioactivity in the pellet and liquid(supernatant). ; infected bacteria passed on DNA; helped prove that DNA is genetic material not proteins (at least for viruses)

Francis Crick

Described the Central Dogma of Gene Expression. DNA to RNA to protein, Cambridge University, works with James Watson, built model of DNA, reclusive, won nobel prize, studies chemical nature of dreams.

Oswald Avery

American Bacteriologist who inspired by Grifith's experiment (Transofrmation), had several experiments that tested if DNA was the genetic material (It Was). Technically not given credit McCarty and Macleod(did announce) but (Hershey and Chase) are usually given credit.

Nucleic Acid

an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information


A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis and as the genome of some viruses.

Frederick Griffith

British Medical officer who performed experiment using 2 varieties of (streptococcus pneumonia) , pathogenic(Smooth -virulent)/ non pathogenic(Rough-non-virulent), that led to discovery of DNA, concluded there was is a TRANSFORMATION from dead bacteria to live bacteria, studied the transforming substance


A change in genotype and phenotype due to the assimilation of external DNA by a cell (Coined by Griffith) . (DO not confuse with other transormation)


The conversion of a normal animal cell to a cancerous cell

James Watson

American scientist. With Francis Crick, he elucidated the structure and function of the DNA double helix. He shared the 1962 Nobel Prize in physiology or medicine with Crick and Maurice Wilkins. He served as the head of the Human Genome Research program from 1989 to 1992.


worked with Avery and Mcleod, they discovered that DNA is what makes chromosomes and genes


Bacteriophage consisting of only DNA and protein. Replicates by invading bacteria(like E- Coli) and using its cellular components to produce progeny. Used in hershey and Chases expiriments.


The liquid on top of material deposited by settling or centrifugation.

Erwin Chagraff

Analyzed the base composition of DNA and saw that it varied from species to species(shows the diversity of species).He also found that the amount of A nucleotides approximately equaled the number of T nucleotides, and the number of C nucleotides approximately equaled the number of G nucleotides. . this became known as Chagraff's rule.

Chagraff's rule.

A rule that thymine combines w/ adenine in equal amounts;and cytosine combines w/ guanine in equal amounts.


Nitrogenous bases that have a single ring of carbon and nitrogen atoms, such as cytosine and thymine


Nitrogeneous bases that have a double ring of carbon and nitrogen atoms such as adenine and guanine

X- Ray Crystallography

A technique that depends on the diffraction of an X-ray beam by the individual atoms of a crystallized molecule to study the three-dimensional structure of the molecule. Helped Watson figure out the double helix of DNA

Double Helix

Shape of a DNA molecule formed when two twisted DNA strands are coiled into a springlike structure and held together by hydrogen bonds between the bases

Watson- Crick Model

DNA consists of two nucleotide strands; strands run in opposite directions 5'=>3' and 3'=>5' (think of 2 magnets together). Strands held together by hydrogen bonds between bases. A binds with T with 2 hydrogen bonds and C with G with three hydrogen bonds. Molecule is a double helix

Semiconservative Model

Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand. (RIGHT). Tested by Matheson and Stahl

Conservative Model

A model based on the hypothesis that when a double helix replicates, the parent strands come back together and there is a completely new daughter strand. (WRONG) Tested by Matheson and Stahl

Dispersive Model

Model that says each strand of both daughter molecules contains a mixture of old and newly synthesized DNA (WRONG) Tested by Matheson and Stahl using istopes of Nitrogen


There are one in _____________ nucleotide base pairs per replication.

Origins of Replication

Sites where the replication of a DNA molecule begins, is where two parental strands separate and form replication bubbles, which expand laterally in both directions. There may be thousands of these in a eukaryote' s DNA.

Replication Bubble

The region where two replication forks are in close proximity to eachother, producing a bubble in the replicating DNA

Replication fork

a Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated

DNA Polymerases

An enzyme that catalyzes the elongation of new DNA at a replication fork by the addition of nucleotides(Nucleoside triphosphate ) to the existing chain at and ONLY at the 3` end.

Nucleoside triphosphate

Molecule consisting of a nitrogenous base, a pentose sugar, and three phosphate groups, e.g., adenosine triphosphate (ATP) only difference is in the sugar(deoxirbose) compared with ribose. Is what is actually added to a growing neuclotide strand by DNA Polymerase


The triphosphate monomers are chemically reactive because their triphosphate tails (-OPO3-) are ____________


when each monomer of dATP joins DNA strand it looses two phosphate groups creating this molecule, and drives the polymerization of DNA.


Parallel, but running in opposite directions. The 5' end of one strand of DNA aligns with the 3' end of the other strand in a double-helix.

DNA Pol 3

Using parental DNA as a template, synthesizes new DNA strand by covalentley adding nucleotides to the 3' end of a pre-existing DNA strand or RNA primer(leading strand). Always makes the new strand 5' to 3'., The Okazaki Fragments are added(after lagging) in the 5' to 3'

Okazaki Fragments

A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication, many of which are joined together to make up the lagging strand of newly synthesized DNA

Lagging Strand

The newly forming daughter strand of DNA that is replicated in a discontinuous fashion, via Okazaki fragments that will ultimately be ligated together; the daugther strand that is replicated in the opposite direction that parallel DNA is unwinding

Leading Strand

The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' 3' direction by DNA Pol 3 .


An enzyme that connects two fragments of DNA (their sugar phosphate backbones) to make a single fragment; also called DNA _____. This enzyme is used during DNA replication and is also used in recombinant DNA research.

Recombinant DNA

DNA in which one or more segments or genes have been inserted, either naturally or by laboratory manipulation, from a different molecule or from another part of the same molecule, resulting in a new genetic combination.


An already existing RNA chain bound to template DNA to which DNA nucleotides are first added during DNA synthesis.


An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.

DNA Pol 1

repairs and patches DNA (5-3 exonuclease activity= clears away short stretched of nucleotides SEVERAL at a time); removes RNA primer as replication forks move and replaces them with DNA.


an enzyme that untwists the double helix at the replication forks, separating the two parental strands and making them available as template strands, after that Topoisomerase relieves the strain caused by the untwisting.


A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, topoisomerase helps to relieve strain in the double helix ahead of the replication fork.

Single Strand binding Protein

A protein that binds to the unpaired DNA strands during DNA replication, stabilizing them and holding them apart while they serve as templates for the synthesis of complementary strands of DNA.

Mismatch Repair

The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides, a heridiatary defect in one of them is associated with colon cancer.


An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides., after it does this the resulting gap is filled in by DNA Pol 1 and ligase which add and cement new nucleotides.

Nucleotide Excision Repair

Enzymes detect damaged DNA, nuclease enzymes cut out the damaged area, DNA polymerase adds nucleotides, ligase completes process by closing the break in the sugar-phosphate backbone

Thymine Dimer

Abnormally chemcally bonded thymine bases in DNA resulting from ultra violet irradion damage. the cellular processes that repair often make errors that cause mutations

Xeroderma Pigmentosum

An Autosomal recessive disease , caused by a defect in the nucleotide excision repair system; Accumulation of damaged DNA; Risk of cancer, a rare genetic condition characterized by an eruption of exposed skin occurring in childhood and photosensitivity with severe sunburn (Mainly from UV )


Prokaryotes do not have a problem with completing the 5` end of daughter strands, because their DNA is ___________


The protective structure at each end of a eukaryotic chromosome. Specifically, the tandemly repetitive DNA at the end of the chromosome's DNA molecule. (TTACGG) in humans, protects the DNA from being eroded ater succesive DNA replications, and somehow activate with other proteins to make sure that the staggered end of the daughter molecule do not activate the cell systems defense for monitoring DNA damage.


The six nucleotide sequence of human teleomeres is __________


An enzyme that catalyzes the lengthening of telomeres. The enzyme includes a molecule of RNA that serves as a template for new telomere segments. Is not active in most cells but is in most of the germ cells which help result in the maximization length of a zygote

Germ Cell

The cell that undergoes meiosis (in humans, only found in the ovaries and testes)

Meselson and Stahl

Proved that DNA replicates in a semiconservative fashion, confirming Watson and Crick's hypothesis. Cultured bacteria in a medium containing heavy nitrogen (15N) and then a medium containing light nitrogen (14N); after extracting the DNA, they demonstrated that the replicated DNA consisted of one heavy strand and one light strand

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